X-ray pulsations from the recently discovered Be/X-ray binary eRASSU J052914.9-662446 in the LMC
ATel #13650; C. Maitra (MPE), F. Haberl (MPE), O. Koenig (ECAP/FAU), V. Doroshenko (IAAT, Tuebingen), S. Carpano (MPE), L. Ducci (IAAT, Tuebingen)
on 21 Apr 2020; 21:34 UT
Credential Certification: Frank Haberl (fwh@mpe.mpg.de)
Subjects: X-ray, Neutron Star, Star, Pulsar
During the beginning of the first all-sky survey (eRASS1), the eROSITA instrument on board the Russian/German Spektrum-Roentgen-Gamma (SRG) mission discovered a new Be/X-ray binary in the Large Magellanic Cloud (LMC) with the classification based on its hard X-ray spectral properties and its spatial coincidence with a Be star (ATel #13610). Following the detection, a NuSTAR observation was performed to further investigate the broad-band X-ray properties of the source. Here we report the discovery of pulsations with a period of ~1412 s in the X-ray flux of eRASSU J052914.9-662446.
The NuSTAR observation was performed between 2020-04-08 (MJD 58947.076) and 2020-04-09 (MJD 58948.29) with an effective exposure of 62.7 ks on FPMA and 62.3 ks on FPMB. Strong pulsations are detected independently in the 3.0 -78.0 keV light curves obtained from FPMA and FPMB thereby confirming the source as an X-ray pulsar. The detected spin period is 1412(5) s where the error corresponds to one sigma confidence. The 3.0-50.0 keV spectrum can be described by an absorbed cutoff-powerlaw model with no additional features, a photon index of 1.2(5), a folding energy of 11(7) keV and an absorption column density of 5(4)×1022 H cm-2. The uncertainties in the spectral parameters correspond to 90% confidence. The observed source flux was ~2.4×10-12 erg cm-2 s-1 in the 3.0-78.0 keV band, corresponding to an absorption-corrected luminosity of ~1036 erg s-1, assuming a distance of 50 kpc. The detailed analysis of NuSTAR and eROSITA data will be published elsewhere.
We thank the NuSTAR SOC team for the quick scheduling of the DDT observation.
